The longhorn pine sawyers, Monochamus saltuarius and M. alternatus (Coleoptera: Cerambycidae), are vectors of the pinewood nematode Bursaphelenchus xylophilus (Nematoda: Parasitaphelenchidae), the causal pathogens of pine wilt disease in Korea. Recently, an aggregation pheromone, 2-(undecyloxy)ethanol, identified from M. galloprovincialis and M. alternatus, was shown to be effective for attracting several Monochamus species in Europe, North America, and East Asia. However, the effect of 2-(undecyloxy)ethanol on attracting M. saltuarius remains largely unraveled. In this study, we investigated the abilities of 2-(undecyloxy)ethanol along with host plant volatiles (α-pinene and ethanol) to attract M. saltuarius at a pine forest in Cheongsong, Gyeongsangbuk-do, Korea. Pine trees in the field experiment site were not previously affected by pine wilt disease. The combination of 2-(undecyloxy)ethanol with host plant volatiles was more effective than either of 2-(undecyloxy)ethanol or host plant volatiles for attracting M. saltuarius. Both sexes of M. saltuarius were attracted to traps containing 2-(undecyloxy)ethanol with the host plant volatiles. Our study suggests that the aggregation pheromone in combination with host plant volatiles could be used for detection and population monitoring of M. saltuarius as well as for effective mass trapping in outbreak situations.